回复：863211 and Pjiang , please

I am Canadian with H1B visa, never apply GC, now I will change my job, the new company only give me TN support, I will go to mexico board to change visa, do you think it is problem?
-You do not need to get the TN visa unless you have dependent who is not a Canadian and need to get the TD visa. You just go to Mexico and return to US and then, get the TN I-94 at the port of entry.

Ask your employer to provide a letter to you,the beneficiary, addressed to the Department of Homeland Security which states the specific TN-approved profession in which the TN beneficiary will be working, a detailed summary of the job responsibilities, salary and anticipated length of stay (up to three years.) The letter should state the minimum degree and experience requirements for the job and describe how the beneficiary is qualified to perform the job.

Then, just bring this letter,your degree diploma, TN fee, and your passport to get the TN I-94 at the port of entry at the US/Mexico border. That is all and no problem at all.